JP5400738B2 - Retransmission device - Google Patents

Description

  The present invention relates to a retransmission apparatus in a joint reception system for television broadcasting.

  Patent Document 1 discloses a technique for modulating the contents of a digital terrestrial broadcast program in an analog broadcast system in a television broadcast joint reception system.

Japanese Patent No. 4464453

  However, when digital terrestrial broadcasting program content is modulated by analog broadcasting, the audio signal input / output standards differ between the digital terrestrial broadcasting device and the analog broadcasting device. Simply connect the input / output terminals for the audio signal. Then, the sound may be distorted.

  Also, in recent television broadcasting, it is common to use a video terrorist or the like for characters, figures and photographs other than the video displayed on the screen. However, when a digital terrestrial broadcast program content is modulated by an analog broadcasting system, if a video, ticker, or the like is used to insert characters, diagrams, or photographs, the video signal and the audio signal are mixed for the processing time required for the insertion. There will be a time delay between them. Due to the generated delay, there has been a problem that the teloped video and audio viewed by the subscriber of the joint reception system are slightly shifted. There is a problem that the video and audio with such a telop are slightly shifted.

  Therefore, the present invention suppresses audio distortion that occurs when digital terrestrial broadcasting is modulated by an analog broadcasting system, and inserts characters, diagrams, and photographs other than images displayed on the screen using a video tipper or the like. Even in such a case, it is an object to provide a re-transmission device that can be viewed without a sense of incongruity without shifting the telop and the video and audio that the subscriber of the joint reception system views.

  In order to solve the above-described problem, a retransmission apparatus according to the present invention is a retransmission apparatus that converts a digital broadcast into an analog broadcast frequency band and retransmits the digital broadcast, and receives the video signal and the audio signal. A digital tuner unit for demodulating, a video IF modulation unit for remodulating the video signal demodulated by the digital tuner unit, an audio IF modulation unit for remodulating the audio signal demodulated by the digital tuner unit, and the video IF A re-modulated video signal output from the modulation unit, and a mixing unit that mixes and outputs the re-modulated audio signal output from the audio IF modulation unit, and the audio IF modulation unit includes the audio signal. Is provided with a compressor section that lowers the degree of modulation of the audio signal (L / M) and the audio signal (R / S).

  Another aspect of the invention is characterized by further including a delay processing unit that is arranged at a subsequent stage of the compressor unit and delays the data of the audio signal by a predetermined time.

  In another aspect of the invention, the delay processing unit is arranged in a stage preceding the FM modulation unit that performs FM modulation on an audio signal.

  In another aspect of the invention, the audio IF modulation unit including the compressor unit and the delay processing unit is a digital circuit.

  In another aspect of the invention, the signal demodulated by the digital tuner unit includes a voice identification signal for selecting monaural, stereo, and multiplex broadcasting. The voice identification signal is transmitted from the digital tuner unit. It is characterized by extracting from the output SP / DIF signal.

  According to the present invention, it is possible to suppress audio distortion by providing a compressor unit that controls the degree of modulation of audio distortion that occurs when digital terrestrial broadcast program content is modulated by an analog broadcasting system.

  In addition, by providing a delay processing unit for the time delay between the video signal containing the telop and the audio signal, it is possible to prevent the video and audio containing the telop viewed by the subscriber of the joint reception system from shifting. It is possible to provide a retransmission apparatus and a retransmission system that can be used.

  Furthermore, by realizing the compressor and delay processing units, which were previously realized with analog circuits, with digital circuits, the noise resistance of audio signals has been improved, and variations in characteristics from product to product have been eliminated. The complicated adjustment process can be greatly reduced.

1 is a block diagram illustrating the principle of a retransmission apparatus 1 according to the present invention. 2 is a block diagram of the IF modulation unit 6. FIG. The block diagram of the audio | voice IF modulation part 11 is shown.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a principle block diagram of the retransmission apparatus 1. 2 shows a detailed block diagram of the IF modulation unit 6 in FIG. 1, and FIG. 3 shows a detailed block diagram of the audio IF modulation unit 11 in FIG.

  FIG. 1 shows a principle block diagram of a retransmission apparatus 1 of the present invention. The retransmitting apparatus 1 includes a digital tuner unit 5 that demodulates digital terrestrial broadcast waves, an IF modulation unit 6 that remodulates the demodulated video and audio signals into analog signals, and a clock generator that generates analog broadcast waves that are currently being broadcast. A synchronous converter unit 2 that down-converts an analog broadcast wave using an internal clock from 4, a carrier reproduction unit 3 that reproduces a carrier wave (carrier signal) from the IF signal down-converted by the synchronous converter unit 2, and an IF modulation unit 6 includes an RF conversion unit 7 that performs amplifier conversion of the analog broadcast IF signal converted at 6 using an internal clock from the clock generation unit 4.

  The digital tuner unit 5 inputs a terrestrial digital broadcast wave received using a UHF antenna (not shown) via the terrestrial digital signal input terminal 42, and receives a video signal and an audio signal from the terrestrial digital broadcast wave TS data. Each of the voice identification signals (SP / DIF) is demodulated. Here, the audio signals include audio (L / M) (left / main) and audio (R / S) (right / sub) signals. The voice identification signal is a signal for selecting monaural, stereo, and multiplex broadcasting.

  As shown in FIGS. 1 and 2, the IF modulation unit 6 mainly includes a video IF modulation unit 10 and an audio IF modulation unit 11. The video signal demodulated by the digital tuner unit 5 is input to the video IF modulation unit 10 and is remodulated by VSB (Vestigial Side Band) -AM, whereby the video signal is converted into an IFV signal. Here, when remodulating, the carrier signal output from the carrier reproducing unit 3 is used to synchronize and modulate the phase of the video carrier signal of the analog broadcast wave currently being broadcast.

  The audio IF modulation unit 11 receives the audio signal demodulated by the digital tuner unit 5 and the audio identification signal. The input audio signal is FM-modulated and converted into an IFA signal. Here, the audio IF modulation unit 11 selects audio signals of audio (L / M) (left / main) and audio (R / S) (right / sub) based on the audio identification signal, and selects monaural, stereo, Automatic switching of multiplex broadcasting.

  In FIG. 1, the video signal output from the digital tuner unit 5 is output to the external connection terminal 44 via the switch 8a. The output video signal is input to the terror device 100, and the video signal output from the terror device 100 is input to the video IF modulator 10 via the external connection terminal 45. In this way, it is possible to insert characters, drawings, photographs, and the like other than images by way of the ticker device 100. The audio signal output from the digital tuner unit 5 is input to the audio IF modulation unit 11 via the switch 8.

  When no character, figure, photograph or the like is inserted, the video signal from the digital tuner unit 5 is directly input to the video IF modulation unit 10 by setting the switch 8a to the SW1 side. Further, by setting the switch 8b to the SW2 side, an audio signal can be output to the external connection terminal 46 and can be connected to an external device (not shown). An audio signal from an external device is input to the audio IF modulation unit 11 via the external connection terminal 47.

  The clock generation unit 4 generates an internal clock with an oscillator or the like, and supplies the internal clock to the synchronous converter 2, the carrier recovery unit 3, and the RF converter unit 7, respectively.

The synchronous converter 2 receives an analog broadcast wave received via a VHF antenna (not shown) and is input via the signal input terminal 41, down-converts it using an internal clock, and converts it into an IF signal. To do. The carrier reproducing unit 3 reproduces a carrier signal from the IF signal. Then, the reproduced carrier signal is supplied to the IF modulator 3.
The RF converter unit 7 up-converts the analog IF signal converted by the IF modulation unit 6 using an internal clock.
Then, the up-converted analog broadcast wave signal (RF signal) is output from the RF output terminal 43.

  As shown in FIG. 1, when a video signal and an audio signal are sent from the digital tuner unit 5 to the IF modulation unit 6, only the video signal passes through the terror device 100, so that only the time required for processing inside the terror device 100 is obtained. The video signal is delayed from the audio signal. When the delay occurs in this way, the video and audio containing the telop that is viewed by the subscriber of the joint reception system is slightly shifted. For this reason, an audio delay processing unit 25 is provided in the IF modulation unit 6 to prevent the video signal and the audio signal from being shifted.

  The audio IF modulation unit 11 of the IF modulation unit 6 will be described in detail with reference to FIG. The audio IF modulation unit 11 includes an A / D 21 and an A / D 22 that convert data of the audio signal (L / M) and the audio signal (R / S) from the digital tuner unit 5 from analog data to digital data, and data An audio level compressor 23 for controlling the degree of modulation of the audio signal, an audio multiplex modulation unit 24 for multiplexing audio signal (L / M) and audio signal (R / S) data, and an audio delay for delaying the audio signal. Processing unit 25, FM modulation unit 26 for FM-modulating the audio signal, D / A 27 for converting FM-modulated audio signal data from digital data to analog data, and FM modulation as an output signal from audio IF modulation unit 11 An up-converting audio signal into an IFA signal, and an audio identification signal (S / DIF) from mono, stereo, and a speech mode extraction unit 29 for extracting a signal for selecting a multiplex broadcasting.

  The A / D 21 and A / D 22 use a commonly used A / D converter with a resolution of 24 bits or the like, and the audio signal (L / M) and the audio signal (R / M) from the digital tuner unit 5 are used. S) is converted from analog data to digital data. In addition, the audio mode extraction unit 29 extracts a signal for selecting monaural, stereo, and multiplex broadcasting from the audio identification signal (SP / DIF) output from the digital tuner unit 5. Compared with the usual method of extracting a speech identification signal from an EPG (Electric Program Guide), switching of the speech mode can be realized more reliably and in real time.

  The audio level compressor 23 lowers the degree of modulation of the audio signal from the digital tuner unit 5 and outputs it to the audio multiplex modulation unit 24. By using this audio level compressor 23, the audio level compressor 23 is output from the digital tuner unit 5. The modulation degree of the audio signal and the modulation degree of the audio signal input to the FM modulation unit 26 are adjusted. By inserting the audio level compressor 23 in this way, it is possible to suppress distortion of the audio. Furthermore, by implementing the audio level compressor 23 by digital processing, the mounting area of the audio IF modulation unit 11 can be reduced, and noise resistance can be improved.

  The audio multiplex modulation unit 24 selects audio signals (L / M) and audio signals (R / S) based on the audio mode information from the audio mode extraction unit 29, and selects monaural, stereo, or multiplex broadcasting. Switch.

  The audio delay processing unit 25 delays the audio signal modulated by the audio multiplex modulation unit 24 by a time required for processing the video signal of the terror device 100. The audio delay processing unit 25 is preferably downstream of the audio multiplex modulation 24 and upstream of the FM modulation unit 26. By arranging the audio delay processing unit 25 in the subsequent stage of the audio multiplex modulation 24 as described above, the multiplexed audio signal (L / M) and audio signal (R / S) can be delayed in a lump. The efficiency can be improved, and the delay process can be performed more easily because the sampling frequency is lower than the subsequent stage of the FM modulation unit 26 by using the previous stage of the FM modulation unit 26. By digitally processing the audio delay processing unit 25, it is possible to easily create an arbitrary amount of delay and to reduce the mounting area of the audio IF modulation unit 11.

  Next, the FM modulation unit 26 generates a 4.5 MHz audio signal, converts it to analog data by the D / A 27, and upconverts it to an IFA signal by the upconverter unit 28.

  As described above, the audio level compressor 23, the audio multiplex modulation 24, the audio delay processing unit 25, the FM modulation unit 26, and the audio mode extraction unit 29, which are normally subjected to analog processing, are each realized by a digital circuit using an FPGA or the like. It is possible to improve the noise resistance of the audio IF modulation unit 11, eliminate variations in characteristics among products, and greatly reduce the complicated adjustment process by performing analog processing.

DESCRIPTION OF SYMBOLS 1 Retransmission apparatus 2 Synchronous converter part 3 Carrier reproduction | regeneration part 4 Clock generation part 5 Digital tuner part 6 IF modulation part 7 RF converter part 8a, 8b Switch 10 Video IF modulation part 11 Audio | voice IF modulation part 12 Mixing part 12
21, 22 A / D
23 audio level compressor 24 audio multiplex modulation unit 25 audio delay processing unit 26 FM modulation unit 27 D / A
28 Up-converter unit 29 Voice mode extraction unit 100 Teloper device

Claims (3)

A retransmission device that converts digital broadcasts into analog broadcast frequency bands and retransmits them,
A digital tuner that receives digital broadcasts and demodulates video and audio signals;
A video IF modulation unit for remodulating the video signal demodulated by the digital tuner unit;
An audio IF modulation unit that remodulates the audio signal demodulated by the digital tuner unit;
A mixing unit for mixing the video signal re-modulated by the video IF modulation unit and the audio signal re-modulated by the audio IF modulation unit;
An RF converter unit that up-converts the video signal and the audio signal mixed in the mixing unit,
The audio IF modulation unit includes a compressor unit that reduces the degree of modulation of an audio signal (L / M) and an audio signal (R / S) included in the audio signal, and the audio signal (L / M) output from the compressor unit. M) and the audio signal (R / S) are multiplexed in accordance with an audio mode of monaural, stereo, or multiplex broadcasting, and a delay processing unit that delays the data of the audio signal by a predetermined time; An FM modulation unit for FM-modulating the audio signal;
The digital tuner unit further demodulates and outputs an SP / DIF signal including a voice identification signal for selecting the voice mode,
The audio IF modulation unit inputs the SP / DIF signal from the digital tuner unit, extracts the audio identification signal, selects the audio mode from the audio identification signal, and outputs the audio mode to the audio multiplex modulation unit A mode extraction unit;
The delay processing unit collectively delays the audio signal multiplexed by the audio multiplex modulation unit at a low sampling frequency before FM modulation by the FM modulation unit. Retransmission device. The retransmission apparatus according to claim 1 , wherein at least the compressor unit, the sound multiplex modulation unit, and the delay processing unit are implemented by a digital circuit and perform digital processing . The video IF modulation unit claims, characterized in <br/> be remodulated to input signal inserting a signal other than the video using Teroppa device to the video signal demodulated by the digital tuner The retransmission apparatus according to 1.

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